I had the same question as you when I came here, I came from a back ground of tillering natural material bows , limb taper,thickness & side tillering etc , but with glass bows it's pretty much the same but the limb taper & thickness is all done prior to glue up ,where what's left is the front view profile & in some cases side tillering & trapping etc , I think of glass bows as internal tiller being in the internal parts & the detail in those for tiller, it's really not a complicated process , good luck with your build !